[Sexyman]

I'm amazed they're still selling fjrs due to euro bs. Unsure your software solution is as good as you think it is.

 

[VFR1200]

I'm amazed they're still selling fjrs due to euro bs. Unsure your software solution is as good as you think it is.

I’ve never tried pulling the front brake in a corner so I wouldn’t know. It seems like the manufacturers have spent a lot of money buying IMUs if it’s just marketing hype.

 

[Griff]

I have recently purchased a 23 Transalp with a 21" front wheel. While getting test rides on that bike I also got a 300km test ride on an 800 Strom again with a 21" front wheel. I own two other bikes with 21" fronts. A CRF300L and an '89 Dominator (NX).

For the purpose of this discussion the two bikes to be compared will be the TA and my '16 Strom 1000 with its 19" front. For me, both bikes are excellent handlers, wet or dry. The Strom is shod with Road 5's and the TA with Karoos. I am equally confident on both in most conditions, but if the road surface starts getting a little iffy then I am more comfortable with the 21" front on the Honda. I feel it has better bite in dirty or loose backroad conditions. Suspension setup has a fair bit to do with the good handling on both bikes. The leaned over grip on tarmac is just as good on one bike as the other and both are excellent. High speed stability on the Honda, even with its mushy suspension and 21" wheel is excellent.

Imho Suzuki are unlikely to put out a dog of a bike with a 21" front wheel just for the sake of sales. I mentioned above that I also tested the 800 Strom with its 21" wheel. Again it was a very enjoyable ride and perfectly stable on the road at speed. My reason for choosing the Honda was weight difference and ergonomics mainly but there was very little in it.

@Spec mentioned above that "You'll get used to whatever wheel size your bike has when you buy it. " He is correct of course.

 

[Steve _H80]

My use case is very long distance touring with the occasional gravel road. I don't really care about serious off-road or twisties. I just want high-speed stability and grip when going fast on the interstate.

Thanks for any insights.

Given your intended use the off-road handling of a 21" wheel isn't going to matter so it comes down to aesthetics vs practicality.
The 21" wheel is a tubed design, the 19" tubeless. Can you fix a tubed puncture at the roadside?

 

[Sladep]

I’ve never tried pulling the front brake in a corner so I wouldn’t know. It seems like the manufacturers have spent a lot of money buying IMUs if it’s just marketing hype.

That would be an interesting experiment that I need to do. I trail brake all the time, and practice panic braking. I get a little wheel chirping and hop when panic braking from ABS, from both front and rear wheels. Next time I'm out, I will go to a good, clean wide-open parking lot and I will try increasingly harder applications of rear and front braking when leaned over far to see how the IMU and ABS do. It's great to know ABS and IMU are there. I don't want to lose my years of braking skills by just becoming lazy and relying on ABS and IMU, but on the other hand, it's really good to know you can crank as hard as possible on both in a crisis and these systems will likely keep you upright. We'll see!

 

[Antique]

I have an ATAS with a 21" and have loved it. Never felt uncomfortable in corners at extreme lean. Doesn't tip in quite as readily as a 19", but couldn't count the times that riding buddies have come over the com on a rough road wishing they had my 21" at the moment.

 

[Spec]

That would be an interesting experiment that I need to do. I trail brake all the time, and practice panic braking. I get a little wheel chirping and hop when panic braking from ABS, from both front and rear wheels. Next time I'm out, I will go to a good, clean wide-open parking lot and I will try increasingly harder applications of rear and front braking when leaned over far to see how the IMU and ABS do. It's great to know ABS and IMU are there. I don't want to lose my years of braking skills by just becoming lazy and relying on ABS and IMU, but on the other hand, it's really good to know you can crank as hard as possible on both in a crisis and these systems will likely keep you upright. We'll see!

I've wondered if the multi axis ABS would accommodate aggressive trail braking.

Report back!

 

[Sladep]

I've wondered if the multi axis ABS would accommodate aggressive trail braking.

Report back!

It should based on what I've read and understand - when the wheel speed varies a certain percentage from the other wheel, the ABS kicks in. Guess I'll be numero uno to find out!

 

[sycamoredave]

Have run bikes with both 19 and 21 wheel. Best compromise is 19. Best gravel is 21. Both work for both. Go with your majority use. Both will be fine. Choice of tires is MUCH more important. Be very focused on matching tires to use. For me, riding an 18 Vstrom 650 XT, Mitas E-07 Dakar covers the bases, with 12k+ tire life. Best wishes and ride safe...

 

[Null 13]

...How does road grip and high-speed stability compare? Brake dive? ...

...My use case is very long distance touring with the occasional gravel road. I don't really care about serious off-road or twisties. I just want high-speed stability and grip when going fast on the interstate...

Can only confirm about a 19" wheel on a 2014 has no issues going to the limiter with oem and regular battlewings. Other tire brands will vary a lot. For instance, my K60 front wobbled very early. Haven't had much emergency braking done so far, but no issues on that front either.

 

[dwfree]

For your intended use, street and good gravel, 19" is far superior - less gyroscopic effect and bigger tire selection. For your use case, street tires would be the best choice, or 80/20. A 17" front would be best, but NA as oem, and would not recommend a retrofit. Stability and grip for fast on the interstate - it ain't gonna matter, 19" or 21" will work fine, but tire selection is the more important factor. The 19" is tubeless, a superior choice for all day hi speed riding, that would make the choice for me.

For street bikes, 17" front has proven to be the best compromise. For dirt, 21" is best. 19" is the ADV compromise.

 

[Spec]

For your intended use, street and good gravel, 19" is far superior - less gyroscopic effect and bigger tire selection. For your use case, street tires would be the best choice, or 80/20. A 17" front would be best, but NA as oem, and would not recommend a retrofit. Stability and grip for fast on the interstate - it ain't gonna matter, 19" or 21" will work fine, but tire selection is the more important factor. The 19" is tubeless, a superior choice for all day hi speed riding, that would make the choice for me.

For street bikes, 17" front has proven to be the best compromise. For dirt, 21" is best. 19" is the ADV compromise.

I think contact patch has more to do with grip than gyro effect.

17" tires are wider typically. Bikes that use them usually have the frame geometry optimized to balanced between stability and turning.

Same with 19 vs. 21 the diameter difference isn't that much but the 19" tires have a wider contact patch.

All bikes generate gyro effects after a certain speed regardless of front wheel size. Frame geometry dictates straight line stability.

 

[VFR1200]

The updated 2024 Africa Twin Adventure Sports now has a 19" tubeless front wheel. Honda update popular Africa Twin adventure range with new looks and revised tech

So Honda is endorsing 19" vs 21" for road riding.

 

[PeteW]

I took on a couple of early AT's with journos on them on my DL650. Now admitted that was a road I knew well that suited the DL to a T but 'annihilated' would be a good description. Very tight and lumpy so all that mattered was stability under braking, cornering and acceleration out of corners. The AT should have had better suspension and ~30HP more than I did so it all came down to how well the bikes cornered.

Which brings up another downside of a 21" wheel, angular momentum is half mr^2. i.e. the amount of force needed to turn the wheel goes up with the square of the wheel radius.

 

[Spec]

I took on a couple of early AT's with journos on them on my DL650. Now admitted that was a road I knew well that suited the DL to a T but 'annihilated' would be a good description. Very tight and lumpy so all that mattered was stability under braking, cornering and acceleration out of corners. The AT should have had better suspension and ~30HP more than I did so it all came down to how well the bikes cornered.

Which brings up another downside of a 21" wheel, angular momentum is half mr^2. i.e. the amount of force needed to turn the wheel goes up with the square of the wheel radius.

I would expect a lighter, smaller engine bike to be more nimble. It's not the front wheel size.

Comparing the 650 to 1000 Strom it's apparent that the 650 turns in easier but the 1000 is more straight line stable. Frame geometry is probably close to the same. The difference is the larger displacement and heavier weight.

My DR 650 is down right twitchy compared to my V 1000. Despite 21" wheel angular momentum... 😁

 

[Deus_Ex_Machina]

Opinions on how a particular bike handles on road with a 21" front wheel are going to vary, some seem to do really well, like Honda's new Transalp, but others are known for being less capable, like the Africa Twin or the F800 GS.

Based on what you described as your usual riding application I would suggest going with the 19" front. The only reason to have a 21" front is if you intend to be more serious about taking the bike off-road, and it doesn't sound like that's really the case for you. I would also suggest that if you're coming from sport bikes you may be more sensitive to the potential handling disadvantages of a 21" front wheel.

 

[dwfree]

I think contact patch has more to do with grip than gyro effect.

Gyro effect has nothing to do with grip. It has to do with stability - resistance to changing direction.

17" tires are wider typically. Bikes that use them usually have the frame geometry optimized to balanced between stability and turning.

Same with 19 vs. 21 the diameter difference isn't that much but the 19" tires have a wider contact patch.

If tire construction is the same, and weight on the front wheel and tire pressure are the same, the contact patches will be equal - different shapes but equal.

All bikes generate gyro effects after a certain speed regardless of front wheel size. Frame geometry dictates straight line stability.

Look up the equations. Gyro effect depends and amount of mass, distance of mass from center, and speed. There is significant difference between the 3 rim sizes in gyro effect. It is a combination of rake, trail, wheelbase, bike mass and centralization of it, and gyro effect to determine stability - it gets complicated.

 

[Spec]

...
If tire construction is the same, and weight on the front wheel and tire pressure are the same, the contact patches will be equal - different shapes but equal.

Wider tires have a wider contact patch.

Look up the equations. Gyro effect depends and amount of mass, distance of mass from center, and speed. There is significant difference between the 3 rim sizes in gyro effect. It is a combination of rake, trail, wheelbase, bike mass and centralization of it, and gyro effect to determine stability - it gets complicated.

It's mostly the speed (RPM) of the tire that generates gyro effect.

There isn't much weight difference between front wheel sizes.

A 21" wheel probably generates slightly more gyro effect than a 17 but all the other aspects you mention have a greater effect on stability.

 

[dwfree]

Wider tires have a wider contact patch.

Wider but shorter. As stated " the contact patches will be equal - different shapes but equal. "

It's mostly the speed (RPM) of the tire that generates gyro effect.

There isn't much weight difference between front wheel sizes.

Yes, gyro effect is directly proportional to angular velocity, ie wheel rpm. It is also a function of the moment of inertia of the wheel, ie where is the weight located. There is substantial difference in gyro effect between the wheel sizes - you can study the physics of it and do the calculations here: Gyroscopes - Everything you needed to know. Its not a question of opinion but scientific fact.

 

[Thunder_Strom]

Haven´t read others opinions.
I did like 45Km test ride to the 1050DE, and now i own a non DE version.
There a well marked difference when making closed curves. I feel much safer in the smaller wheels.
Its not just the wheels, the suspension travel is also greater in the DE (not to mention wight), so also a taller center of gravity.
If you think of doing Mostly pavement roads... go for the 19" in the front.
I tested many models and brands, ultimately i choose Strom 1050, so... great machines!